Materials often exhibit a variety of different failure mechanisms. On occasion, materials are loaded beyond a tensile strength of the material and the material fractures abruptly and completely. In these circumstances the material is usually non-repairable and must be replaced. However, often materials do not fail in an abrupt complete manner, but rather fail due to fatigue or localized stresses which exceed design criteria, causing cracks to form in the material. Often when these cracks initially form, the material is still functional for its desired purpose. For instance, a reciprocating machine may receive cracks in its structural material and yet continue to operate, albeit at perhaps a lesser efficiency. Cracks thus serve as indicators that a material is being over stressed and yet also provides an opportunity for remedial measures to be taken without requiring entire replacement of the affected material.
Where the crack passes through a preexisting hole, however, such as through a stud hole, or worse, a spark plug hole, a severe problem exists.
Crack repair pins are known in the art which are threaded into holes drilled and tapped in the cracks to prevent cracks from continuing to propagate. U.S. Pat. No. 5,379,505 (issued to the present inventor) provides one example of these crack repair pins. These crack repair pins have been effective in resealing materials such as cast iron casings which require that they maintain a somewhat pressurized environment without allowing fluids to escape therefrom.
In addition, locks are known in the art which can draw cracks together somewhat and extend the life of the material which is cracked. One example of this can be found in the inventor's U.S. Pat. No. 4,662,806.
However, neither of these solutions nor the prior art which applicant is aware address a threaded hole which needs repair to receive a threaded fastener and specifically, the repair of a threaded hole in which a crack has propagated therethrough. Where the threaded hole is a spark plug hole, the problem is quite severe because of the internal pressures within the combustion chamber.
For example, a damaged threaded hole in which a threaded fastener is to be received in needs to be strengthened to a level which effectively allows the threaded fastener to be rigidly retained therein. In addition, the damaged threaded hole may need to be repaired to a level which allows parts to be coupled to one another to effectively provide a seal which will withstand a pressurized environment. Furthermore, the damaged threaded hole may be disposed in a material at a location which requires the walls of the hole to provide means to maintain a somewhat pressurized environment without allowing fluids to escape therefrom.
The following prior art reflects the state of the art of which applicant is aware and is included herewith to discharge applicant's acknowledged duty to disclose relevant prior art. It is stipulated, however, that none of these references teach singly nor render obvious when considered in any conceivable combination the nexus of the instant invention as disclosed in greater detail hereinafter and as particularly claimed.
PATENT NO. ISSUE DATE INVENTOR 83,341 October 27, 1868 Foster 154,864 September 8, 1874 Harvey 250,728 December 13, 1881 Harvey 310,462 January 6, 1885 Patten 568,277 September 22, 1896 Rall 678,814 July 16, 1901 Riggs 899,916 September 29, 1908 Smith 1,345,425 July 6, 1920 Wells 1,408,793 March 7, 1922 Anderson, et al. 1,434,870 November 7, 1922 Brubaker, Jr. 1,539,628 May 26, 1925 Bayer 1,543,007 June 23, 1925 Hanson 1,963,542 June 19, 1934 Bergstrom 2,011,484 August 13, 1935 Harman 2,121,692 June 21, 1938 Hays 2,291,162 July 28, 1942 Kirby 2,300,310 October 27, 1942 Poeton 2,361,701 October 31, 1944 Michaels 2,506,233 May 2, 1950 Murphy 2,649,650 August 25, 1953 Javor 2,951,506 September 6, 1960 Diperstein 2,998,645 September 5, 1961 Diperstein 3,066,400 December 4, 1962 Forsythe 3,295,580 January 3, 1967 Waltermire 3,660,233 May 2, 1972 Dalke, et al. 4,074,950 February 21, 1978 Holmes 4,271,554 June 9, 1981 Grenell 4,599,781 July 15, 1986 Diperstein 4,662,806 May 5, 1987 Reed 4,824,279 April 25, 1989 Casazza 4,845,828 July 11, 1989 Reed 4,892,429 January 9, 1990 Giannuzzi 5,033,919 July 23, 1991 Choe 5,379,505 January 10, 1995 Reed FOREIGN PATENT DOCUMENTS UK 350,141 June 11, 1931 Arenz IT 456,481 December 1950 AU 154,074 November 10, 1953 Metalock of Australia SU 492,389 January 22, 1976 Ivanov Furniture SU 975,270 November 28, 1982 Mosc Auto Mech Inst.
The other prior art listed above but not specifically described further catalog the prior art of which the applicant is aware. These references diverge even more starkly from the references specifically distinguished above.